1. Field of the Invention
The present invention relates to a temperature sensor, a method of manufacturing the temperature sensor, a semiconductor device, a method of manufacturing the semiconductor device, and a method of controlling the semiconductor device.
2. Description of the Related Art
As an instrument to measure temperature, a thermistor or the like, which can output an electric signal corresponding to a measured temperature, is widely used in various electronic apparatuses. When a semiconductor device is used in an electronic apparatus, the electronic apparatus may be subject to a relatively strict temperature management or control, because properties of a semiconductor material that constitutes the semiconductor device are likely to change depending on temperature.
A semiconductor device in which the thermistor or the like is integrated in order to measure a temperature of the semiconductor device has been disclosed in Japanese Patent Application Laid-Open Publications Nos. S63-80546, H03-195058, and 2007-134684.
A temperature sensor based on the thermistor or the like is different in terms of its structure from a semiconductor device such as a semiconductor memory and a logic circuit. Specifically, different materials from those generally used to fabricate the semiconductor device need to used, and different processes from those generally performed to fabricate the semiconductor device need to be performed, in order to integrate such a temperature sensor on the same substrate from which the semiconductor device is fabricated. Therefore, the semiconductor device integrated with the temperature sensor tends to be expensive.
The present invention has been made in view of the above, and is directed to provide a compatible temperature sensor integrated in a semiconductor device such as a memory and a logic circuit at a low cost, and a method of manufacturing the temperature sensor. In addition, the present invention is directed to provide a semiconductor device in which the temperature sensor is integrated, a method of manufacturing the semiconductor device, and a method of controlling the semiconductor device.
According to a first aspect of the present invention, there is provided a temperature sensor comprising a charge trap structure including a silicon oxide film formed on a substrate; an aluminum oxide film that is formed on the silicon oxide film, wherein oxygen is injected into the aluminum oxide film from an upper surface thereof; and an electrode formed on the aluminum oxide film, wherein a flat band voltage of the charge trap structure is temperature dependent.
According to a second aspect of the present invention, there is provided a method of manufacturing a temperature sensor comprising steps of forming a silicon oxide film on a substrate; forming an aluminum oxide film on the silicon oxide film; injecting oxygen into the aluminum oxide film from an upper surface thereof; and forming an electrode on the aluminum oxide film to which the oxygen has been injected.
According to a third aspect of the present invention, there is provided a semiconductor device comprising: a semiconductor element area where a semiconductor element is formed, wherein the semiconductor element includes a charge trap structure including a silicon oxide film formed on a substrate; an aluminum oxide film that is formed on the silicon oxide film, wherein oxygen is injected into the aluminum oxide film from an upper surface thereof; and an electrode formed on the aluminum oxide film, and a temperature sensor area where the temperature sensor according to the first aspect is formed.
According to a fourth aspect of the present invention, there is provided a method of manufacturing a semiconductor device according to the third aspect. The method comprises steps of: forming a silicon oxide film on a substrate; forming an aluminum oxide film on the silicon oxide film; injecting oxygen selectively into the aluminum oxide film in the temperature sensor area; and forming an electrode on the aluminum oxide film in the temperature sensor area and the semiconductor element area.
According to a fifth aspect of the present invention, there is provided a method of controlling a semiconductor device according to the third aspect. The method comprises steps of: measuring a temperature in the temperature sensor area; determining whether the measured temperature is a predetermined temperature or greater; and performing one of cooling the semiconductor device and transferring data stored in the memory area of the semiconductor device to another device when determined affirmative in the step of determining.
According to a sixth aspect of the present invention, there is provided a method of controlling the semiconductor device according to the third aspect. The method comprises steps of measuring a temperature in the temperature sensor area; determining one of a pulse width and a voltage of a signal applied to the semiconductor element area in accordance with the measured temperature; and writing data into the semiconductor element area in accordance with one of the pulse width and the voltage determined in the step of determining.